- Guanidinum chloride as dehydrocyclization agent in the synthesis of 2-fuctionalized (4H)-3,1-benzoxazine-4-ones
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A facile and expedient route for the synthesis of 2-ethoxy- and 2-(ethylcarboxylate)-(4H)-3,1-benzoxazine-4-ones is described using guanidinium chloride as a safe and convenient dehydrocyclization agent. High yields of the products obtain under mild react
- Nikpour, Farzad,Bahmani, Asrin,Havasi, Forugh,Sharafi-Kolkeshvandi, Mahnaz
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- A phosgene and peroxide-free one-pot tandem synthesis of isatoic anhydrides involving anthranilic acid, boc anhydride and 2-chloro-N-methyl pyridinium iodide
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A phosgene and peroxide-free approach for the synthesis of isatoic anhydrides has been described. The synthesis involves the carbamate formation with boc anhydride followed by in situ cyclization to afford the isatoic anhydride. The importance of this synthetic strategy is in the ease of operation, scalability and preparation from readily available raw materials.
- Verma, Chhaya,Sharma, Somesh,Pathak, Arunendra
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p. 6897 - 6899
(2019/04/10)
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- Ester vs. amide on folding: A case study with a 2-residue synthetic peptide
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Although known for their inferiority as hydrogen-bonding acceptors when compared to amides, esters are often found at the C-terminus of peptides and synthetic oligomers (foldamers), presumably due to the synthetic readiness with which they are obtained using protected peptide coupling, deploying amino acid esters at the C-terminus. When the H-bonding interactions deviate from regularity at the termini, peptide chains tend to "fray apart". However, the individual contributions of C-terminal esters in causing peptide chain end-fraying goes often unnoticed, particularly due to diverse competing effects emanating from large peptide chains. Herein, we describe a striking case of a comparison of the individual contributions of C-terminal ester vs. amide carbonyl as a H-bonding acceptor in the folding of a peptide. A simple two-residue peptide fold has been used as a testing case to demonstrate that amide carbonyl is far superior to ester carbonyl in promoting peptide folding, alienating end-fraying. This finding would have a bearing on the fundamental understanding of the individual contributions of stabilizing/destabilizing non-covalent interactions in peptide folding.
- Vijayadas, Kuruppanthara N.,Nair, Roshna V.,Gawade, Rupesh L.,Kotmale, Amol S.,Prabhakaran, Panchami,Gonnade, Rajesh G.,Puranik, Vedavadi G.,Rajamohanan, Pattuparambil R.,Sanjayan, Gangadhar J.
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p. 8348 - 8356
(2013/12/04)
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- A convenient synthesis of anthranilic acids by Pd-catalyzed direct intermolecular ortho-C-H amidation of benzoic acids
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An efficient method for synthesis of anthranilic acids by Pd-catalyzed ortho-C-H amidation of benzoic acids is disclosed. The amidation is proposed to proceed by carboxylate-assisted ortho-C-H palladation to form an arylpalladium(ii) complex, followed by nitrene insertion to the Pd-C bond.
- Ng, Ka-Ho,Ng, Fo-Ning,Yu, Wing-Yiu
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supporting information
p. 11680 - 11682,3
(2012/12/12)
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- A simple and expedient method for the stepwise synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones
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A simple and practical route is described for the synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones using the coupling reaction of anthranilic acid derivatives with diethyl dicarbonate following with fast cyclization of the carbamate adduct with a dehydro
- Bahmani, Asrin,Sharafi-Kolkeshvandi, Mahnaz,Nikpour, Farzad
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experimental part
p. 434 - 437
(2012/05/20)
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- Novel alternative for the N-N bond formation through a PIFA-mediated oxidative cyclization and its application to the synthesis of indazol-3-ones
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The synthesis of a series of N,N′-disubstituted indazolone derivatives starting from methyl anthranilates is presented. This general approach features a novel and easy way for access to the target N-heterocycles by formation of a new N-N single bond. The
- Correa, Arkaitz,Tellitu, Imanol,Dominguez, Esther,SanMartin, Raul
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p. 3501 - 3505
(2007/10/03)
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- Direct conversion of azides to carbamates and sulfonamides using Fe/NH4Cl: Effect of sonication
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A simple, direct and effective conversion of azides to carbamates and sulfonamides is achieved using Fe/NH4Cl in methanol. The influence of sonication and direct application in solution phase combinatorial chemistry are also studied by developing a 6x4 matrix library. (C) 2000 Elsevier Science Ltd.
- Chandrasekhar,Narsihmulu
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p. 7969 - 7972
(2007/10/03)
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- Solid phase synthesis of chiral 3-substituted quinazoline-2,4-diones
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The synthesis of chiral 3-substituted quinazoline-2,4-diones was performed starting from N-urethane anthranilamides. This synthetic pathway was applied in solid phase, from commercially available anthranilic acid that was bound to hydroxymethyl polystyrene resin via a carbamate linker. In both cases, cyclisation occurred under basic conditions to afford non-racemized quinazolinediones in high purity.
- Gouilleux, Laurent,Fehrentz, Jean-Alain,Winternitz,Martinez, Jean
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p. 7031 - 7034
(2007/10/03)
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- Novel use for carbamoyl benzoates
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Novel alkoxycarbonylamino benzoates and related copounds (carbamoyl benzoates) are disclosed for treatment of auto-immune disease states, such as arthritis.
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- Cyanic Acid Ester. 35. On Formation and Consecutive Reactions of N-Cyanato Phthalimide. New Specifically Activated and Blocked Isatoic Acid Derivatives
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Depending on the reaction conditions N-hydroxy-phthalimide affords on treatment with cyanogen bromide via N-cyanato phthalimide 2 the iminocarbonate 3 and isatoic acid derivatives 7 and 16.Both the latter react with nucleophiles as isatoic acid derivatives activated on the carboxylic group and protected on the carbamic group or vice versa, furnishing N,N-bis alkoxycarbonyl anthranilic acid amides 9, N-alkoxycarbonyl anthranilic acid 12, o-alkoxycarbonyl phenyl ureas 17 and the benzotriazepin-2,5-dione 14.The structures of the new compounds are proved by 1H-n.m.r. and 13C-n.m.r. measurements as well as independent synthesis.
- Martin, Dieter,Nadolski, Karin,Gruendemann, Egon
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p. 737 - 746
(2007/10/02)
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- Triazolothiadiazoloquinazolin-6-one
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3-Methyl-6H-triazolothiadiazoloquinazolin-6-one (6) has been synthesized by the condensation of isatoic anhydride (1) with 4-amino-5-mercapto-3-methyl-triazole (2) and final cyclisation of the intermediate 3 with POCl3 and PCl3.Alternatively 6 could also be synthesized by the condensation of 3-amino-2-mercapto-3H-quinazolin-4-one (7) with N-carbethoxyhydrazine in presence of hydrochloric acid and final cyclisation of the intermediate 8 with acetic acid.The structures have been confirmed on the basis of IR, PMR and analytical results. - Keywords: Heterocycles; Infrared; 1H-NMR
- Gakhar, H. K.,Jain, Anju,Gill, J. K.,Gupta, Shashi Bhushan
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p. 339 - 342
(2007/10/02)
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